Hello 
Please, with this recording sample I want more clear voice without surround and echo
How can I do it with Audacity 2.3.3 ? wich filter ?
I want only voice of speaker as clear as possible…
Many Thanks.
Audacity can’t remove reverberation or echoes.
That sounds like an add-on reverb effect.
De-Reverb plugin$ do better with those than real-world reverberation, but the end result is obviously processed …
Many thanks 
… I will try it and try after compression + equalizer… 
Compression will make reverb worse: it will make the decay longer.
An expander (which is the opposite of a compressor) would hasten the decay of the reverb, but won’t get rid of it.
Equalizer won’t make any difference: the reverb has the same frequency content as the voice.
Ok Trebor
Last question please: Can Audacity isolate voice ?
many thanks
Not in the example you’ve provided.
If the recording was stereo sometimes vocal isolation is possible.
https ://manual.audacityteam.org/man/tutorial_vocal_removal_and_isolation.html
Does this help?
Sometimes you can use Noise Reduction in strange ways.
I selected some of the echo-only at 4 seconds and used that as the profile. Select the whole clip > Effect > Noise Reduction > 12-6-6.
Then I selected some of the echo at 1-1/2 seconds. Select the whole clip > Effect > Noise Reduction > 12-6-6.
The clip isn’t very long, but I noticed the echo takes the character of the hall, not just the speaker. You can use that to attack the echo without damaging the voice too much.
Koz
This may be a little better. I used the Profiles from the same places, but I used a gentler Noise Reduction of 9-6-6.
It’s a little less likely to dump the volume when his voice goes down at the end.
Koz
Thank you very very much guys 